System for vibration damping of a fuel nozzle within a combustor

ABSTRACT

A system for vibration damping a fuel nozzle within a combustor includes a support plate, a fuel nozzle passage that extends through the support plate and a cylindrical damping insert that is coaxially aligned within the fuel nozzle passage and at least partially defines the fuel nozzle passage. The damping insert may include a metallic-mesh liner.

FIELD OF THE INVENTION

The present invention generally relates to a combustor for use in a gas turbine. More particularly, this invention relates to a fuel nozzle support collar for reducing fuel nozzle vibration.

BACKGROUND OF THE INVENTION

A typical gas turbine includes an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section. The inlet section cleans and conditions a working fluid (e.g., air) and supplies the working fluid to the compressor section. The compressor section progressively increases the pressure of the working fluid and supplies a compressed working fluid to the combustion section. The compressed working fluid and a fuel are mixed within the combustion section and burned in a combustion chamber to generate combustion gases having a high temperature and pressure. The combustion gases are routed along through a hot gas path into the turbine section where they expand to produce work. For example, expansion of the combustion gases in the turbine section may rotate a shaft connected to a generator to produce electricity.

The combustion section generally includes a plurality of combustors annularly arranged and disposed between the compressor section and the turbine section. An outer casing at least partially surrounds the combustors and each combustor includes an end cover that is coupled to the outer casing. At least one axially extending fuel nozzle extends downstream from each end cover within the outer casing. An upstream or forward end of the fuel nozzle is rigidly connected to the end cover. In some combustor configurations, a downstream or aft end of the fuel nozzle is generally unsupported, thereby creating a cantilever. In alternate designs, the aft end of the fuel nozzle may be at least partially supported within an opening in a cap assembly that extends radially and axially within the outer casing downstream from the end cover.

During operation of the gas turbine, various factors such as combustion dynamics, rotor vibration and/or flow induced excitation may cause the cantilevered fuel nozzle to vibrate at various resonant frequencies which may affect fuel nozzle/combustor durability due to high cycle fatigue related issues. Various systems and methods have been deployed and/or considered to dampen the cantilevered fuel nozzles. For example, one system includes spring supports to shift or increase the natural frequency of the fuel nozzle. Other attempts to shift or increase the natural frequency of the fuel nozzle have included connecting the aft end of the fuel nozzle to a rigid structure within the combustor using a tether or braided wire.

Although the systems previously mentioned are generally effective, each may require additional hardware and add complexity to new combustor designs. In addition, the systems previously mentioned may not be practical for retrofitting existing combustor designs. Accordingly, an improved system for damping a fuel nozzle within a combustor of a gas turbine would be useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.

One embodiment of the present invention is a system for vibration damping a fuel nozzle within a combustor. The system includes a support plate, a fuel nozzle passage that extends through the support plate and a cylindrical damping insert that is coaxially aligned within the fuel nozzle passage and at least partially defines the fuel nozzle passage.

Another embodiment of the present invention is a combustor for a gas turbine. The combustor generally includes an outer casing and an end cover that is coupled to the outer casing and a fuel nozzle that extends downstream from the end cover within the outer casing. A cap assembly extends radially and axially within the outer casing. The cap assembly includes a support plate and a cap plate that is disposed downstream from the support plate. The cap plate includes an opening. A fuel nozzle passage extends through the support plate and is aligned with the opening in the cap plate. The fuel nozzle extends at least partially through the fuel nozzle passage and the opening. A cylindrical damping insert is coaxially aligned with the fuel nozzle passage and extends circumferentially around the fuel nozzle.

Another embodiment of the present invention includes a gas turbine. The gas turbine includes a compressor and a combustor that is disposed downstream from the compressor. The combustor includes an outer casing, an end cover coupled to the outer casing and a fuel nozzle that extends axially downstream from the end cover within the outer casing. A turbine is disposed downstream from the combustor. The gas turbine further includes a system for vibration damping of the fuel nozzle. The system is disposed within the outer casing downstream from the end cover. The system includes a support plate, a fuel nozzle passage that extends through the support plate, and a cylindrical damping insert coaxially aligned within the fuel nozzle passage. The damping insert comprises a metallic-mesh liner that circumferentially surrounds a portion of the fuel nozzle. The damping insert at least partially defines the fuel nozzle passage.

Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

FIG. 1 is a functional block diagram of an exemplary gas turbine within the scope of the present invention;

FIG. 2 provides a simplified cross section side view of an exemplary combustor that may incorporate various embodiments of the present invention;

FIG. 3 provides a cross section perspective view of an exemplary combustor that incorporates various embodiments of the present invention;

FIG. 4 provides a prospective view of a system for vibration damping of a fuel nozzle within a combustor as shown in FIG. 3, according to one embodiment of the present invention;

FIG. 5 provides an exploded perspective view of the system for vibration damping of a fuel nozzle within a combustor as shown in FIG. 4;

FIG. 6 provides a cross section perspective view of a portion of the combustor as shown in FIG. 3, according to one embodiment of the present disclosure;

FIG. 7 provides a perspective view of a damping insert according to at least one embodiment of the present disclosure;

FIG. 8 provides a perspective view of a damping insert according to one embodiment of the present disclosure;

FIG. 9 provides a perspective view of a portion of the combustor as shown in FIG. 3, including the damping insert as shown in FIG. 8;

FIG. 10 provides a perspective view of the system for vibration damping of a fuel nozzle within a combustor including an alternate embodiment of the damping insert, according to one embodiment of the present disclosure; and

FIG. 11 provides an enlarged cross section perspective view of a portion of the damping insert as shown in FIG. 10, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention.

As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream,” “downstream,” “radially,” and “axially” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. Similarly, “radially” refers to the relative direction substantially perpendicular to the fluid flow, and “axially” refers to the relative direction substantially parallel to the fluid flow. The term “circumferentially” refers to a relative direction that extends around an axial centerline of a particular component.

Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures, FIG. 1 provides a functional block diagram of an exemplary gas turbine 10 that may incorporate various embodiments of the present invention. As shown, the gas turbine 10 generally includes an inlet section 12 that may include a series of filters, cooling coils, moisture separators, and/or other devices to purify and otherwise condition a working fluid (e.g., air) 14 entering the gas turbine 10. The working fluid 14 flows to a compressor section where a compressor 16 progressively imparts kinetic energy to the working fluid 14 to produce a compressed working fluid 18 at a highly energized state.

The compressed working fluid 18 is mixed with a fuel from a fuel supply 20 to form a combustible mixture within one or more combustors 22. The combustible mixture is burned to produce combustion gases 24 having a high temperature and pressure. The combustion gases 24 flow through a turbine 26 of a turbine section to produce work. For example, the turbine 26 may be connected to a shaft 28 so that rotation of the turbine 26 drives the compressor 16 to produce the compressed working fluid 18. Alternately or in addition, the shaft 28 may connect the turbine 26 to a generator 30 for producing electricity. Exhaust gases 32 from the turbine 26 flow through an exhaust section 34 that connects the turbine 26 to an exhaust stack 36 downstream from the turbine 26. The exhaust section 34 may include, for example, a heat recovery steam generator (not shown) for cleaning and extracting additional heat from the exhaust gases 32 prior to release to the environment.

The combustors 22 may be any type of combustor known in the art, and the present invention is not limited to any particular combustor design unless specifically recited in the claims. FIG. 2 provides a simplified cross-section side view of an exemplary combustor 22 that incorporates various embodiments of the present invention. As shown in FIG. 2, a casing 40 and an end cover 42 may combine to contain the compressed working fluid 18 flowing to the combustor 22 from the compressor 16 (FIG. 1). The compressed working fluid 18 may pass through cooling holes 44 in an annular flow sleeve 46 such as an impingement sleeve or a combustion flow sleeve to flow along the outside of a transition duct 48 and/or a liner 50 towards the end cover 42.

At the end cover 42, the compressed working fluid 18 reverses flow direction. A portion of the compressed working fluid 18 is routed through at least one fuel nozzle 52 where a fuel is injected into the compressed working fluid 18 to provide a combustible mixture 54. The combustible mixture 54 is injected into a combustion chamber 56 for combustion. In particular embodiments, the combustor 22 includes an annular cap assembly 58 that at least partially surrounds a portion of the fuel nozzle 52. The cap assembly 58 may be connected to the outer casing 40.

FIG. 3 provides a cross section perspective view of an exemplary combustor 22 that incorporates various embodiments of the present invention. As shown in FIG. 3, the combustor 22 may include a plurality of fuel nozzles 52 that extend generally axially downstream from an inner surface 60 of the end cover 42. The fuel nozzles 52 are typically cantilevered from the end cover 42. For example, a forward or upstream end 62 of each fuel nozzle 52 is rigidly connected to the end cover 42.

As shown, the cap assembly 58 generally extends radially and axially within the outer casing 40 downstream from the end cover 42. In particular embodiments, the cap assembly 58 includes a cap plate 64 disposed at an aft/downstream end 66 of the cap assembly 58. An aft or downstream portion 68 of each fuel nozzle 52 extends at least partially through a corresponding opening 70 that extends through the cap plate 64. The cap plate 64 is generally disposed adjacent to the combustion chamber 56 (FIG. 2).

In various embodiments, as shown in FIG. 3, the combustor 22 includes a system for vibration damping of the fuel nozzles 52, herein referred to as “system 100.” FIG. 4 provides a prospective view of the system 100 as shown in FIG. 3 according to one embodiment, and FIG. 5 provides an exploded perspective view of the system 100 as shown in FIG. 4. As shown in FIGS. 4 and 5, the system 100 includes a support plate 102, at least one fuel nozzle passage 104 that extends through the support plate 102 and at least one cylindrically shaped damping insert 106 that is substantially coaxially aligned within the fuel nozzle passage 104 with respect to an axial centerline 108 of the fuel nozzle passage 104. In one embodiment, as shown in FIG. 3, the support plate 102 and/or the system 100 may be provided as part of the cap assembly 58.

In particular embodiments, as shown in FIGS. 4 and 5 the system 100 includes at least one retaining plate 110. The retaining plate 110 generally extends circumferentially around at least a portion of the fuel nozzle passage 104 so as to retain the damping insert 106 in position. The fuel nozzle passage 104 may be at least partially defined by an outer collar 112 that at least partially circumferentially surrounds the fuel nozzle passage 104. The outer collar 112 generally extends axially outward from the support plate 102. The outer collar 112 may at least partially surround the damping insert 106. In particular embodiments, as shown, the system 100 may include a plurality of fuel nozzle passages 104, a plurality of damping inserts 106, a plurality of retaining rings 110 and a plurality of outer collars 112 as described herein.

In one embodiment, as shown in FIG. 5, the damping insert includes an outer sleeve 114 that at least partially surrounds a metallic-mesh liner 116. The metallic-mesh liner 116 may include any material such as wire-mesh, metallic-mesh and/or metallic-fabric that has suitable thermal and damping properties for the intended purpose of the present invention and that is suitable for use within the operating environment of the combustor. For example, the metallic-mesh material may comprise of a high performance alloy or super alloy such as an austenitic nickel-chromium-based alloy

FIG. 6 provides a cross section perspective view of a portion of the combustor 22 as shown in FIG. 3. In one embodiment, the damping insert 106 extends circumferentially around the fuel nozzle 52 within the fuel nozzle passage 104. In this embodiment, the metallic-mesh liner 116 is in direct contact with the fuel nozzle 52. During operation of the gas turbine, combustion dynamics, rotor vibration and/or flow induced excitation may cause the cantilevered fuel nozzle 52 to vibrate at various resonant frequencies, thereby loading individual fibers throughout the metallic-mesh liner 116. As a result, friction coulomb damping occurs to reduce vibration amplitudes of the fuel nozzle 52, thereby increasing overall combustor durability.

FIG. 7 provides a perspective view of the damping insert 106 according to at least one embodiment of the present disclosure. As shown, the damping insert 106 may further include an inner sleeve 118. The inner sleeve 118 may be coaxially aligned within the outer sleeve 114. The metallic-mesh liner 116 is disposed between the inner sleeve 118 and the outer sleeve 114. The inner sleeve 118 and the outer sleeve 114 may comprise of any material suitable for the intended purpose as described herein. For example, the inner sleeve 118 and the outer sleeve 114 may comprise of a stainless steel or other alloy having suitable wear and thermal properties.

As shown in FIG. 7, the damping insert 106 may also include an expansion joint or slot 120 to allow for expansion around the fuel nozzle 52 during installation/assembly. In this manner, the damping insert 106 may be slightly undersized so as to provide a spring force around the fuel nozzle 52 (FIG. 3), thereby ensuring contact between the damping insert 106 and the fuel nozzle 52 during operation of the gas turbine 10. In addition, the expansion joint 120 helps to avoid potential misalignment issues to assembly tolerances.

FIG. 8 provides a perspective view of the damping insert 106 according to one embodiment of the present disclosure, and FIG. 9 provides a perspective view of a portion of the combustor 22 as shown in FIG. 3, including the damping insert 106 as shown in FIG. 8. As show in FIGS. 8 and 9, the damping insert 106 may include at least one step or retaining feature 122 that extends at least partially around the outer sleeve 114. As shown in FIG. 9, the retainer plate 110 extends at least partially across the retaining feature 122 so as to retain the damping insert 106 in the fuel nozzle passage 104. As shown in FIG. 9, the outer collar 112 may include a complementary step feature 124 configured to engage with the retaining feature 122 of the damping insert 106.

FIG. 10 provides a perspective view of the system 100 including an alternate embodiment of the damping insert 106 according to one embodiment of the present disclosure, and FIG. 11 provides an enlarged cross section perspective view of a portion of the damping insert 106 as shown in FIG. 10. As shown in FIG. 10, the damping insert 106 may include a retaining ring 126. The retaining ring 126 at least partially defines the fuel nozzle passage 104. The retaining ring 126 may be fixed to the support plate 102 by any means known in the art that is suitable for the intended purpose of the invention. For example, the retaining ring 126 may be brazed, bolted or brazed to the support plate 102. As shown in FIG. 11, the retaining ring 126 generally surrounds and/or at least partially encases the metallic-mesh liner 116. In particular embodiments, the metallic-mesh liner 116 is disposed between the inner sleeve 118 and the retaining ring 126.

The various embodiments as disclosed herein and as illustrated in FIGS. 3 through 11 provide various technical benefits over existing technologies. Specifically, this invention takes advantage of the damping characteristics of metallic-mesh, wire mesh or other metallic fabrics to reduce vibration in the fuel nozzle. For example, when the fuel nozzle begins to vibrate, the individual fibers throughout the metallic-mesh rub against each other resulting in friction coulomb damping, thereby reducing vibration amplitudes of the fuel nozzles. As a result, overall mechanical performance of the combustor and/or the fuel nozzle is improved by reducing the potential of high cycle related issues, in particular with extended length fuel nozzles. In addition, the system may be retrofitted into existing combustor designs with minimal additional hardware or hardware modification required. In addition, the metallic-mesh does not impose problems usually associated with axial and or radial thermal expansion because the thermal growth may be accommodated by the metallic-mesh material.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other and examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed:
 1. A system for vibration damping a fuel nozzle within a combustor, comprising: a. a support plate; b. a fuel nozzle passage that extends through the support plate; and c. a cylindrical damping insert coaxially aligned within the fuel nozzle passage, wherein the damping insert at least partially defines the fuel nozzle passage.
 2. The system as in claim 1, wherein the damping insert comprises a metallic-mesh liner.
 3. The system as in claim 2, wherein the damping insert comprises an annular inner sleeve and an annular outer sleeve, the metallic-mesh liner being disposed between the inner sleeve and the outer sleeve.
 4. The system as in claim 2, wherein the damping insert comprises an outer sleeve that at least partially surrounds the metallic-mesh liner.
 5. The system as claim 2, wherein the damping insert comprises an annular ring that surrounds the metallic-mesh liner, wherein the annular ring is coupled to the support plate.
 6. The system as in claim 5, wherein the damping insert comprises an inner sleeve coaxially aligned within the annular ring, the metallic-mesh liner being disposed between the inner sleeve and the annular ring.
 7. The system as in claim 1, wherein the damping insert includes an expansion gap.
 8. The system as in claim 1, wherein the damping insert includes an outer sleeve having at least one retaining feature, the system further comprising a retaining plate that extends circumferentially around at least a portion of the fuel nozzle passage, wherein the retainer plate extends at least partially across the retaining feature.
 9. A combustor for a gas turbine, comprising: a. an outer casing and an end cover that is coupled to the outer casing; b. a fuel nozzle that extends downstream from the end cover within the outer casing; c. a cap assembly that extends radially and axially within the outer casing, the cap assembly having a support plate and a cap plate disposed downstream from the support plate, the cap plate having an opening; d. a fuel nozzle passage that extends through the support plate, wherein the fuel nozzle extends at least partially through the fuel nozzle passage and the opening of the cap plate; and e. a cylindrical damping insert coaxially aligned within the fuel nozzle passage, wherein the damping insert extends circumferentially around the fuel nozzle.
 10. The combustor as in claim 9, wherein the damping insert comprises a metallic-mesh liner.
 11. The combustor as in claim 10, wherein the damping insert comprises an annular inner sleeve and an annular outer sleeve, the metallic-mesh liner being disposed between the inner sleeve and the outer sleeve.
 12. The combustor as in claim 10, wherein the damping insert comprises an outer sleeve that at least partially surrounds the metallic-mesh liner.
 13. The combustor as in claim 10, wherein the damping insert comprises an annular ring that surrounds the metallic-mesh liner, wherein the annular ring is coupled to the support plate.
 14. The combustor as in claim 13, wherein the damping insert comprises an inner sleeve coaxially aligned within the annular ring, the metallic-mesh liner being disposed between the inner sleeve and the annular ring.
 15. The combustor as in claim 10, wherein the damping insert includes an expansion gap.
 16. A gas turbine, comprising: a. a compressor; b. a combustor downstream from the compressor, the combustor having an outer casing, an end cover coupled to the outer casing and a fuel nozzle that extends axially downstream from the end cover within the outer casing; c. a turbine disposed downstream from the combustor; and d. a system for vibration damping of the fuel nozzle, wherein the system is disposed within the outer casing downstream from the end cover, the vibration damping system comprising: i. a support plate; ii. a fuel nozzle passage that extends through the support plate; and iii. a cylindrical damping insert coaxially aligned within the fuel nozzle passage, the damping insert comprising a metallic-mesh liner that circumferentially surrounds a portion of the fuel nozzle, wherein the damping insert at least partially defines the fuel nozzle passage.
 17. The gas turbine as in claim 16, wherein the damping insert comprises an annular inner sleeve and an annular outer sleeve, the metallic-mesh liner being disposed between the inner sleeve and the outer sleeve.
 18. The gas turbine as in claim 17, wherein the damping insert includes an expansion gap.
 19. The gas turbine as in claim 16, wherein the damping insert comprises an outer sleeve that at least partially surrounds the metallic-mesh liner.
 20. The combustor as in claim 10, wherein the damping insert comprises an annular ring that surrounds the metallic-mesh liner, wherein the annular ring is coupled to the support plate. 